Could not autowire FeignClient in service

Question

I have a simple API who it uses a FeignClient to call on other api and get an access token. However today i don't understand why my client is null.

Can you explain why on run, my feign client is null ?

@SpringBootApplication
@EnableFeignClients
public class App {

    public static void main(String[] args) {
        SpringApplication.run(App.class, args);
    }
}

My Controller

@RestController
@RequestMapping("/api")
public class AppController {

    private final MyService myService = new MyService();
}

My Service

@Service
public class MyService {

    @Autowired
    private MyClient myClient;

  public AccessToken applicationLogin(final LoginParameters loginParameters) {
        return myClient.getAccessToken(loginParameters);
    }
}

My client

@FeignClient(name = "myClient", url = "https://myurl.com")
public interface MyClient {

    @PostMapping("/auth/login")
    AccessToken getAccessToken(@RequestBody LoginParameters loginParameters);
}

Error

Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause java.lang.NullPointerException: null

Ravik · Answer 1 · 2021-10-14T15:29:02.687

1

You are using wrong variable to invoke the method instead of r2aClient you should ise myClient

public AccessToken applicationLogin(final LoginParameters loginParameters) {
    return myClient.getAccessToken(loginParameters);
}

Edit based in new changes

I guess the @EnableFeignClient is not able to find the class MyClient, try @EnableFeignClient(basePackages = "<your package for MyClient>)

edited Oct 14 '21 at 15:29

answered Oct 14 '21 at 14:53

Ravik

694
7
12

That was a mistake on copy / paste – A.Rouze Oct 14 '21 at 14:56
You may accept the answer as well, if it resolved the issue – Ravik Oct 14 '21 at 15:14
No, this is not resolved. That was a bad copy / paste in stackoverflow.. i edited my initial post – A.Rouze Oct 14 '21 at 15:22
I have updated my answer, if it doesn’t help request you to share the code so I can have a look and get the root cause – Ravik Oct 14 '21 at 15:30

UKoehler · Answer 2 · 2021-10-14T15:40:19.490

1

I think you have to inject the Service in your Controller. You created your Service as a normal Java-class so the MyClient is not injected.

@RestController
@RequestMapping("/api")
public class AppController {
    @Autowired
    private final MyService myService;
}

edited Oct 14 '21 at 15:40

answered Oct 14 '21 at 15:35

UKoehler

131
7

score 0 · Answer 3 · answered Jan 10 '22 at 03:36

do not use

new MyService();

if use 'new',it will not be managed by spring. you could check it by

@RestController
public class MyController {
    
    private IMyService iMyService = new MyServiceImpl();
}

@Service
public class MyServiceImpl implements IMyService {

   @Autowired
   private MyMapper myMapper;

  //....

}

myMapper will always be null.cuz you create it by new. by the way,since Spring 4,field injection is not recommended

Could not autowire FeignClient in service

3 Answers3